Good evening everyone!
Tropical Disturbance INVEST 97L continues to become somewhat better organized, especially during the last few hours. There has been quite an increase in convection over the past 24 hours. Based on the 1800Z update of ATCF FTP data, and satellite loop imagery, the following data was available on INVEST 97L, and is plotted on the Global Tracks 7 Tracking map:
Analysis of IR2 Shortwave satellite imagery loops indicate the convection is now just on the eastern edge of this LLC, and the satellite appearance may suggest a center reformation could be occurring under the convection, and notable in the low level winds based on low level steering with satellite overlay. The NHC has designated a MEDIUM (40%) chance of this INVEST becoming a tropical cyclone during the next 48 hours.
The current wind shear map from CIMSS indicates upper level conditions are not as favorable as a few hours ago, when an upper level anticyclone was established over the system, however the upper level wind pattern does indicate an outflow jet north and south
of the center of the convection.
The most recent run of the GFS wind shear forecast indicates upper level winds should become very favorable for further development in about 2-3 days, and could be over INVEST 97L should it track based on the current forecast steering layers maps.
Water Vapor satellite loop imagery does indicate dry air directly north of the disturbance, however, INVEST 97L will be entering an area of higher TCHP once it crosses the Lesser Antilles. This may be enough heat energy to allow 97L to moisten the atmosphere around it enough to survive.
Based on these analysis parameters, I feel 97L will continue to become slowly organized, and could potentially organize at a more steady rate once in the central and western Caribbean areas.
The 18Z run of the Dynamic Model Guidance only displayed one model, which has 97L heading off to the NW in a couple of days. Based on the steering layers forecast at the moment, I must discount this, as steering suggest a motion toward the WSW in about 48 hours or so, then back toward the west thereafter.
Two things we will need to monitor on this, the strength of this system, and whether or not the steering follows the GFS forecast currently, or the CMC. SHOULD there not be any changes, the GFS steering suggests a continued west to WNW near the end of the period, and this could affect somewhere near Nicaragua or Honduras. The CMC solution places it in a position where there could be a possible U.S. threat. Two longwave trofs are forecast to move north of the system, and depending on how strong these may be, and the strength of the system, will determine which model right now shows the best solution. However, BEAR IN MIND…steering goes out to 6 days, so this is just an estimate based on just this one run. Steering factors can change in a matter of 24 hours…so at the moment, this is more of a message to keep this in the back of your mind.
I will have another update in the a.m. sometime.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)